Vitamin D may Prevent
Multiple Sclerosis
January 13, 2004 (ABC
Science Online)
Vitamin D, which the body
makes when exposed to sunlight, may help
prevent multiple sclerosis (MS) and rheumatoid arthritis, two studies
suggest.
The findings may help explain why the two autoimmune diseases are more
common in northern climes, where sunlight is often scarce, the researchers
said.
In a study released in today's issue of the journal Neurology, the
researchers found women who took multivitamins containing vitamin D were 40%
less likely to develop multiple sclerosis than women who did not take
supplements.
"Because the number of cases of MS increases the farther you get from
the equator, one hypothesis has been that sunlight exposure and high levels
of vitamin D may reduce the risk of MS," said Kassandra Munger of the
Harvard School of Public Health in Boston, who led the study.
"These results need to be confirmed with additional research, but it's
exciting to think that something as simple as taking a multivitamin could
reduce your risk of developing MS."
MS sclerosis is a crippling disease caused when the immune system, for
unknown reasons, mistakenly damages the myelin, the protective fatty sheath
around nerves.
Symptoms range from tremors to paralysis to memory loss and vary from person
to person. There are treatments that help, but no cure.
Munger's team looked at two studies involving 187,000 nurses. A total of 173
developed MS over a 20-year period.
The nurses with the highest intake of vitamin D from supplements (400 IU or
more a day) were 40% less likely to develop MS than those who used no
supplements. The women who only got vitamin D from food such as fortified
milk did not lower their risk of MS.
Preventing rheumatoid arthritis
A second study, published in the journal Arthritis & Rheumatism, showed that
vitamin D may prevent rheumatoid arthritis, another autoimmune disease in
which the joints are attacked and destroyed.
The 11-year study of 29,368 women aged 55-69 found that 152 women developed
rheumatoid arthritis.
The women whose diets were highest in vitamin D had the lowest occurrence of
the disease, the researchers at the University of Iowa, the University of
Alabama at Birmingham and elsewhere found. Again, supplements seemed to be a
better source than food, they reported.
The vitamin may somehow affect the immune system, the researchers said.